Abstract— Energy and water crisis affects every aspect of modern human life, and thus, addressing both in one solution is a growing trend. Merging hybrid renewable energy systems (HRES) and water desalination system in one system is a promising solution. In this paper, optimization of stand-alone hybrid photovoltaiv (PV) systems for powering a house equipped with a reverse osmosis (RO) water desalination system in Sinak village, Tehran, Iran, is discussed. RO system configuration, regular house load and RO deferrable load, solar radiation capability and HRES components have been analyzed in the first part of this paper. The second part deals with optimization, cost analysis and sensitivity analysis – using HOMER Pro software – of two HRES scenarios equipped with RO: i) a PV system with battery storage and ii) a PV system with battery storage and a gas generator. Moreover, different dispatch strategies for controlling the investigated systems – namely cycle charging (CC) and load following (LF) – are described. In the last part, a comparison between the two scenarios is performed. The obtained results show that the hybrid PV-battery-RO system is more energy-effective, has less control complexity and has a capability of meeting the load demand with with zero carbon emissions. Results of the conducted economic analysis reveal that the system has a net present cost (NPC) and a cost of electricity (COE) of 10,245 US$ and 0.31 US$/kWh, respectively, while fewer sensitivity variables affect the system’s cost.